This invention relates to a process for producing 2,3-dimercaptopropane-1-sulfonic acid having the formula ##STR1## and its salts.
2,3-dimercaptopropane-1-sulfonic acid and its salts are useful in treating cases of poisoning by highly toxic metal salts. This is particularly true of the sodium salt (hereafter abbreviated as Na-DMPS). Among the metal toxins which may be treated are mercury, cadmium and lead salts. These compounds are also effective in treating poisoning by antimony and arsenic compounds. Compounds produced according to the process of the invention, especially Na-DMPS, exhibit a high therapeutic index and have a substantially lower toxicity than other antidotes which are utilized in treating poisoning by the aforementioned agents.
M. S. Johary and L. N. Owen, J. Chem. Soc. (London) 1307 (1955) describe the production of Na-DMPS by reacting a 2,3-dibromopropane-1-sulfonic acid intermediate with sodium thioacetate. A disadvantage of this procedure is the fact that sodium thioacetate is very expensive. Additionally, this known procedure produces neither pure products or satisfactory yields. However, in view of the aforementioned utility of 2,3-dimercaptopropane-1-sulfonic acid and its salts, it is of substantial importance to obtain pure products; and in view of the exceptional effectiveness of these compounds and the limited capacity of known processes to produce them, there is additionally a need for a process for making such compounds which enables the achievement of economically viable yields of very pure product.
It is an object of the present invention to provide a process for making 2,3-dimercaptopropane-1-sulfonic acid and its salts which produces high yields of pure product.
It is also an object of the invention to provide a process which is simple and can be carried out economically.